When loaded, the center of gravity of the truck shifts to the rear, which requires an appropriate redistribution of braking forces. This function is performed by a load sensing/bypass valve (LSP & BP) (refer to accompanying illustration).
Due to the fact that special measuring equipment is required for adjustment and maintenance of the LSP &BP, this work should be entrusted to a car service specialist. However, valve replacement may well be done by the owner of the car on their own (to adjust the LSP &BP, the car will still have to be driven to a workshop). When removing the rear axle, you should also remember to disconnect the LSP &BP ride height monitoring rod from it (if other valve settings have not been changed, then stem disconnection should not lead to a violation of the adjustments).
Removal and installation
LSP &BP Valve Installation Details
Attention! After performing a valve replacement, the vehicle should be driven to a workshop to have the LSP &BP adjusted.
1. Jack up the car and put it on stands.
2. Loosen the union nuts of the brake line unions on the LSP &BP valve assembly (refer to illustration above), use a special ring wrench with a split head. Carefully disconnect the hydraulic lines, plug open ends immediately.
3. Give a counternut and disconnect an adjusting bolt from the rear suspension arm.
4. Loosen the mounting bolts and remove the LSP &BP valve assembly with its support bracket.
5. Give fixing nuts and remove valve assembly from a basic arm.
6. Installation is carried out in the reverse order. Follow the correct setting of the initial length of the spring and the reliability of tightening the lock nut (refer to accompanying illustration).
7. Bleed the brake system (see Section Bleeding the brake system).
8. Drive the vehicle to a workshop to have the LSP &BP adjusted.